title: High miR-21 expression in breast cancer associated with poor disease-free survival in early stage disease and high TGF-beta1.
abstract: MicroRNA-21 (miR-21) is considered an onco-microRNA given its abilities to suppress the actions of several tumor suppressor genes and to promote tumor cell growth, invasion and metastasis. Recently, transforming growth factor-beta (TGF-beta) is found to up-regulate the expression of miR-21, and elevated miR-21 expression is seen frequently in breast cancer. To evaluate the effect of miR-21 on disease progression and its association with TGF-beta, we analyzed miR-21 expression in breast cancer. Fresh tumor samples were collected during surgery from 344 patients diagnosed with primary breast cancer. The expression of miR-21 in tumor samples was measured with a TaqMan microRNA assay using U6 as reference. Levels of miR-21 expression by disease stage, tumor grade, histology, hormone receptor status and lymph node involvement were compared. Cox proportional hazards regression analysis was performed to assess the association of miR-21 expression with disease-free and overall survival. The study results showed that the expression of miR-21 was detected in all tumor samples with substantial variation. High miR-21 expression was associated with features of aggressive disease, including high tumor grade, negative hormone receptor status, and ductal carcinoma. High miR-21 was also positively correlated with TGF-beta1. No associations were found between patient survival and miR-21 expression among all patients, but high miR-21 was associated with poor disease-free survival in early stage patients (HR = 2.08, 95% CI: 1.08-4.00) despite no value for prognosis. The study supports the notion that miR-21 is an onco-microRNA for breast cancer. Elevated miR-21 expression may facilitate tumor progression, and TGF-beta may up-regulate its expression.
authors.affiliation: Department of Epidemiology and Public Health, Yale Cancer Center, Yale University School of Medicine, New Haven, CT 06520-8034, USA.
authors.forename: Biyun
authors.initials: B
authors.lastname: Qian
authors.forename: Dionyssios
authors.initials: D
authors.lastname: Katsaros
authors.forename: Lingeng
authors.initials: L
authors.lastname: Lu
authors.forename: Mario
authors.initials: M
authors.lastname: Preti
authors.forename: Antonio
authors.initials: A
authors.lastname: Durando
authors.forename: Riccardo
authors.initials: R
authors.lastname: Arisio
authors.forename: Lina
authors.initials: L
authors.lastname: Mu
authors.forename: Herbert
authors.initials: H
authors.lastname: Yu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D053208:Kaplan-Meier Estimate; D035683:MicroRNAs / Q000096:biosynthesis*; D008875:Middle Aged; D009367:Neoplasm Staging; D016133:Polymerase Chain Reaction; D011379:Prognosis; D016016:Proportional Hazards Models; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D053773:Transforming Growth Factor beta1